As is known in the art, there is a need for transferring relatively large amounts of data (>1 Gb/sec) between satellite/sensors, unmanned aerial vehicle (UAVs), aircrafts, ships and ground. Potential applications include airborne networking backbone for GIG extension and US Navy high data rate reach-back for military, downloading of satellite gathered data for NASA/NOAA, and border monitoring or disaster recovery communications for homeland security.
To satisfy the requirements of such disparate applications, it is necessary to have a hybrid elctro-optical/radio frequency (EO/RF) aperture (HERA) that combines electro-optics (EO) and RF circuitry in a common aperture. This approach saves real estate and simplifies pointing and tracking algorithms. Furthermore, it is desirable for the HERA aperture to be conformal to a fuselage of an aircraft or unmanned aerial vehicle (UAV) or other body. In aircraft applications, conformal antennas reduce drag and volume.
Prior attempts to provide a HERA include systems such as that manufactured by Mission Research Corporation (MRC). The MRC approach comprises an RF horn having an optical beam disposed through a sidewall of the horn. Such a system can provide a common mechanical motion for both EO and RF that are co-boresight. Another prior art system manufactured by Schaeffer includes a 50 cm optical telescope disposed on a reflector of a Global Hawk Ku-band communications reflector antenna. This approach also provides a common mechanical motion for both EO and RF that are co-boresight. Both of the above systems have common EO/RF apertures. However, neither system is conformal and both require significant volume.
U.S. Pat. No. 7,388,551, describes multiple variable inclination continuous transverse stub (VICTS) antennas (generally described as outer and middle VICTS antenna) which provide simultaneous communication with multiple remote sites. However, in the structure described in the '551 patent, non-radiating RF conductors are required to connect the stubs separated by the middle VICTS antenna(s). Special care of routing the conductors around the middle VICTS antennas is needed since each VICTS antenna is rotating in the azimuth plane.
It would, therefore, be desirable to provide to a conformal, a hybrid electro-optic/radio frequency (EO/RF) system having a common RF/EO aperture which requires a relatively small volume.